Flood barriers prevent invading water on a flooding side of the barrier from reaching a protected side of the barrier. They are used where flooding waters occasionally occur, such as an area subject to an occasional unusually high tide, a storm surge, a springtime swollen river, or anywhere a flood may occur.
A good flood barrier has several attributes. A flood barrier must generally be high enough to prevent water (or other flooding fluid) from breaching or cresting above the top of the barrier, and it should be sufficiently sealed or waterproof enough to allow only an amount of water through the barrier that is negligible for the application at hand. Perhaps less obviously, the barrier should be strong enough to withstand the substantial horizontal force from a standing or even surging water body on the flooding side of the barrier. It must withstand this force without bursting or even just sliding laterally toward the protected side of the barrier.
Traditional flood barriers include large permanent installations, such as levees or dikes, and may consist simply of a large mound of dirt or of concrete and steel walls. In areas where flooding is less frequent, a flood barrier may preferably be non-permanent, such that it can be deployed when a flood is threatened and removed once the threat is gone. Such deployable barriers can be used for infrequent flooding threats, for example, to protect a single building in a town where a permanent levee may fail, or to protect an area from the unexpected flooding from a town's water main pipe break. A common deployable flood barrier is a simple pile of sand bags.
FIG. 1 depicts a more sophisticated prior art removable flood barrier, as presented in U.S. Pat. No. 7,121,764. As depicted in FIG. 1, the prior art barrier 1 includes a solid wall 5, a solid support plate 13, and a gasket 12. The solid wall 5 and solid support plate 13 are large and heavy, making storage and installation a challenge. Additionally, gasket 12 must be included to provide an effective seal against flooding water and may be 2″ or more thick. The gasket 12 requires pressure prior to flooding, which in FIG. 1 is provided by sandbag 14.